This invention relates to a control system for a testing device for the automatic transmissions used in automobiles and the like, and in particular relates to a control system for an automatic transmission testing device that enables the automatic transmission to be subjected to drive and load conditions that substantially simulate the conditions encountered in an actual automobile.
In prior automatic transmission testing devices, the speed of the driven side, i.e. the input shaft of the transmission under test, was controlled, while a flywheel accelerated or decelerated by an electric motor acted as a load on the output shaft of the transmission. The drive torque, accordingly, was determined by the speed of the change in the speed reference or control signal. In other words, the drive torque depended on the acceleration or deceleration time setting. Thus, the accuracy of the torque setting on the input shaft side was poor, and the setting could not be varied with accuracy. Further, at the shift point, an important parameter of automatic transmission performance, the rotational speed of the input shaft changes substantially within a very brief space of time, but being under speed control, it reverts to the specified speed (that at which the shift occurred), making it impossible to easily maintain the output shaft at the speed required for measurement.